Pi-allyldinitrosyliron complexes of germanium,tin and lead



United States Patent 3,448,129 ar-ALLYLDINITROSYLIRON COMPLEXES F GERMANIUM, TIN AND LEAD Perry L. Maxfield, Bartlesville, 0kla., assignor to Phillips Petroleum Company, a corporation of Delaware No Drawing. Filed Sept. 2, 1966, Ser. No. 576,821 Int. Cl. C07f 15/02, 7/24, 7/22 US. Cl. 260-429 2 Claims This invention relates to a novel catalyst, and to a dimerization process employing said catalyst. In one of its aspects, the invention relates to new complex 1r-allylic compounds of iron.

In another aspect, the invention relates to the dimerization of unsaturated hydrocarbons in the presence of a catalyst comprising complex 1r-allylic compounds of iron.

In another aspect, the invention relates to the homodimerization of acyclic conjugated dienes containing up to about 12 carbon atoms per molecule by contacting said conjugated dienes with the complex catalyst of this invention.

In another aspect, the invention relates to the codimerization of two different conjugated dienes by contacting these compounds with a complex catalyst comprising complex w-allylic compounds of iron.

In another aspect, the invention relates to the essentially quantitative production of 4-vinylcyclohexene by contacting 1,3-butadiene with the complex catalyst of this invention at temperatures substantially lower than those required to dimerize 1,3-butadiene without a catalyst.

Numerous catalysts have been proposed to dimerize conjugated dienes such as 1,3-butadiene, to higher molecular weight cyclic unsaturated compounds such as 4-vinylcyclohexene. For example, the reaction of 1,3-butadiene takes place very slowly at ambient temperatures without a catalyst While at temperatures above 100 C. the conversion is rapid and accompanied by higher molecular weight polymerization products. It is an object of this invention to provide a new dimerization process and a catalyst therefor which can be used at moderate temperatures to produce essentially quantitative yields, that is, without formation of other polymeric by-products. A further object of the invention is to provide a long lasting catalyst for homoand co-dimerization processes. It is a particular object of the invention to provide a catalyst, and a process employing said catalyst, for the formation of vinylcyclohexene from 1,3-butadiene in high yields at moderate temperatures.

Other aspects, objects, and the several advantages of the invention will be apparent to one skilled in the art from studying the specification and claims.

In accordance with the invention, a new compositions of matter is provided having the formula:

to the iron atom and in which -R is hydrogen or a methyl radical; M is one of tin, lead, or germanium; and X is one of chloride, bromide, iodide, or a a-bonded hydrocarbon radical preferably having up to 20 carbon atoms. The a-bonded hydrocarbon radicals are aliphatic or cycloaliphatic or aromatic. Examples are:

Allyl Phenyl Benzyl 4-tolyl 4-methyl-6-heptynyl Cyclopentyl l2-eicosenyl Z-naphthyl 3,448,129 Patented June 3, 1969 Said complex composition of matter has particular utility as a catalyst for the dimerization of conjugated dienes.

As used herein, the term dimerization refers to homodimerization of acyclic conjugated dienes, and to the codimerization of two different acyclic conjugated dienes. A specific example of the novel complex compounds of this invention is bis(1r-allyldinitrosyliron)tin dichloride, whose structure is believed to be 1 01 f NO l ONF|eSn-Fe NO (Note: represents ar-bonded allyl radical.)

Another novel catalytic composition is bis(1r-allyldinitrosyliron)allyltin chloride whose structure is believed to be Other examples of the novel compounds provided by this invention include:

bis(1r-allyldinitrosyliron)germanium dibromide bis(vr-methallyldinitrosyliron) germanium dichloride bis (1r-crotyldinitrosy1iron) tin diiodide bis (Ir-fillYldiIliifOSYlll'Ol'l lead dichloride bis [1r- (2-rnethylcrotyl dinitrosyliron lead dibromide bis(vr-methallyldinitrosyliron)tin chloride bromide bis(r-allyldinitrosyliron)methyl tin bromide bis(vr-methallyldinitrosyliron)phenylgermanium chloride bis(vr-crotyldinitrosyliron)benzyllead iodide bis [1r-(2-methylcrotyl) dinitrosyliron14-tolyltin chloride bis(1r-allyldinitrosyliron)4-methyl-6-heptynyllead bromide bis(1r-allyldinitrosyliron)cyclopentyltin chloride bis(1r-methallyldinitrosyliron)IZ-eicosenyltin chloride bis(1r-allyldinitrosyliron) 2-naphthylgermanium iodide.

The method of preparing these novel compositions broadly comprises reacting ,u,;t'-dihalotetranitrosyldiiron (the dimer of dinitrosyliron halide) and an allyl or substituted allylmetal or halide compound. These compositions can be prepared by several methods:

METHOD A Under an inert atmosphere, an equimolar mixture of ;t, .'-dihalotetranitrosyldiiron (halo-chloro, brorno, or iodo) and an allyl, methallyl, crotyl, or Z-methylcrotyl compound of tin, germanium, or lead is mixed in the presence of any suitable inert diluent, preferably an inert hydrocarbon such as benzene. Any order of addition can be used, as well as any convenient temperature and pressure, room temperature and atmospheric pressure being convenient. It is preferred that the mixture be allowed to stand at least one hour after the initial mixing before it is used in a catalytic reaction. During the standing period a fine precipitate may settle out. This may be removed, if desired, for convenience by centrifugation or filtration.

The catalytic solution is somewhat air and moisture sensitive and should be kept under an inert atmosphere.

0 It should be used within a few days of its preparation from the above solution by conventional crystallization techniques. The isolated and dried solid is relatively stable to the atmosphere and has a considerably longer shelf life than its solution.

METHOD B Under an inert atmosphere, 1 mole of ,u,,u.'-dihalotetranitrosyldiiron (as above), 1 mole of tin, germanium, or lead dihalide (chloride, bromide, iodide), 2 moles of allyl, methallyl, crotyl, or 2-methylcrotyl chloride, bromide, or iodide, and \at least mole of Al powder (or its equivalent in other reducing metals, such as powdered Zn, Fe, Mg, or reducing compounds such as cobaltocene) are mixed, in any order, in the presence of any suitable inert solvent, tetrahydrofuran being particularly suitable. After mixing the solution is stirred, preferably for several hours under any convenient conditions such as room temperature or higher. The solution is then used as the solution of Method A.

METHOD C Under an inert atmosphere are mixed 1 mole of u,pf-dihalotetranitrosyldiiron, 2 moles of powdered tin, germanium, or lead metal, and 2 moles of an allylic halide (as above) in an inert solvent such as tetrahydrofuran. After a suitable reaction period, 1-10 hours at room temperature for example, the solution is used as the solution of Method A.

METHOD D Under an inert atmosphere are mixed 2 moles of Roussins black salt KFe S (NO) (or 3 moles of Roussins red salt [Fe(NO) SEt*] 6 moles of cadmium halide, 3 moles of a tetrallylic tin, germanium, or lead compound, and at least 3 moles of powdered zinc or its METHOD E To prepare the catalytic compounds having a hydrocarbon radical a-bonded to the tin, germanium, or lead atom, one mole of the products obtained from Methods A through D (whether isolated solid or in solution) is treated with 1-2 moles of hydrocarbyl magnesium halide or a hydrocarbyl alkali metal, alkaline earth metal, or aluminum compound. The treatment is carried out in any suitable solvent, such as the ethers or hydrocarbons previously mentioned, at temperatures generally lower than room tempenature. After a reaction time of at least about one hour, the solution can be used in a catalytic process or the catalytic composition can be isolated by crystallization. Both the solution and isolated solids are preferably protected from the atmosphere and both the solution and solid should be utilized within a few days.

The n,;t'-dihalotetranitrosyldiiron reagents used in the above synthesis techniques can be prepared by any conventional method known in the art. A particularly convenient procedure is that described in copending Ser. No. 518,018, filed Jan. 3, 1966. If desired, the preparation of the pf'dihalotetranitrosyldiiron compound and the complex 1r-allylic iron compounds of the present invention can be sequentially prepared in the same vessel and in the same solvent without isolation of the former.

Method A has been used to synthesize some of the novel compounds of this invention: For example, by contacting ,u, .-dichlorotetranitrosyldiiron with tetrallyltin in the presence of benzene, bis(1r-allyldinitrosyliron)tin dichloride is formed. By treating this compound with 4 allylmagnesium bromide (Method B), bishwallyldinitrosyliron)allyltin chloride is formed.

As an example of Method B, ,u,n-dibromotetranitrosyldiiron is contacted with powdered aluminum metal in the presence of lead(II) chloride and methallylchloride to give bis(methallyldinitrosyliron)lead dichloride. When this compound is contacted with phenylsodium, bis(methallyldinitrosyliron)phenyllead chloride is obtained.

As an example of Method C, u-dichlorotetranitrosyldiiron is mixed with powdered germanium and crotyl bromide in the presence of tetrahydrofuran, resulting in the production of bis(qr-crotyldinitrosyliron)germanium dibromide. Treatment of this compound with butyllithium results in the production of bis(w-crotyldinitrosyliron) butylgermanium bromide.

As an example of Method D, KFe S (NO) is mixed with tetraallyltin, cadmium iodide, powdered zinc, and sodium borohydride in ethyl ether to produce a solution containing bis(ar-allyldinitrosyliron)tin diiodide.

The conjugated dienes to which this process is directed include those acrylic conjugated dienes having up to about 12 carbon atoms per molecule, or mixtures thereof. Some specific examples of these are: 1,3-butadiene, isoprene, piperylene, 2,3-dimethylbutadiene-1,3, 1,3-hexadiene, 2,4,-octadiene, 2-methylpentadiene-1,3, 4-ethyldecadiene-1,3, and the like.

According to the dimerization process of this invention, the conjugated diene is contacted with the catalyst at a temperature within the range of from about 0 to about C., preferably 20-60 C. The contact can be carried out either batchwise or continuously using any conventional contacting apparatus. In batch reactions, the catalyst mixtures can be prepared either in the reaction vessel before the addition of the conjugated diene or in a separate vessel and then pumped to the dimerization vessel. The dimerization can be carried out at any convenient pressure which is sufficient to maintain a substantially liquid state. Pressures ranging from 0 to about 1,000 p.s.i.g. can be used. The contact time will vary according to the efficiency of the contacting technique, the reaction temperature, and the desired degree of conversion, but will generally be in the range of from about 1 minute to about 10 hours, preferably 30-90 minutes. The catalyst usage will be in the range of from about 0.001 to 10, preferably 0.01-1 millimole of iron per mole of conjugated diene. Diluents, such as ethers and inert hydrocarbons, can be used in the reaction zone but the reaction is preferably carried out substantially in the absence of substantial amounts of diluent.

After completion of the reaction, the dimeric products are recovered by any conventional technique such as by fractionation, crystallization, adsorption, and the like. If desire'd, the crude reaction product can be treated first with an aqueous inorganic acid to destroy and/or remove the catalyst.

The invention can be further illustrated by the following examples.

EXAMPLE I Preparation of bis(1r-allyldinitrosyliron)tin dichloride The title compound was prepared by mixing 4 ml. of a tetrahydrofuran solution of p,n'-dichlorotetranitrosyldiiron, 10 ml. dry benzene, 1.0 ml. of tetraallyltin, and 0.25 ml. thiophene. After standing for several days, the mixture was centrifuged to remove inorganic solids which had precipitated and then cooled to 78 C. to produce orange crystals. Recrystallization from warm toluene gave about 0.75 g. of crystals, M.P. 132 C. with decomposition. In other runs, it was found that the thiophene could be omitted without affecting the results.

Elemental analysis calculated for C H Cl 'Fe' N O Sn showed the following:

Calculated: C H Cl Fe N O Sn.-C, 14.30; H, 2.00; Cl, 14.08; Fe, 22.18; N, 11.12; Sn, 23.62; Mol. wt, 503.7.

6 Found: C, 14.7; H, 2.2; Cl,14.4; Fe, 23.1; N, 10.7; Sn, poured slowly into the heated solution. After heating in 21.7; Mol. wt., 487. hot water bath (ES-90 C.) for 30 minutes, the mixture The tetrahydrofuran solution of the fl-dichlorotetrawas filtered hot, 10 ml. of 30 percent potassium hydroxide nitrosyldiiron reagent used in the above synthesis was solution was added and it was allowed to stand at room prepared by treating a mixture of 16 g. (0.1 mole) of 5 temperature for 20 hours. The black crystals were re anhydrous ferric chloride and g. iron powder under covered by filtration and recrystallized from acetone and nitrogen with 65 ml. of tetrahydrofuran. The resulting dried for 24 hours over tridecylaluminum, yielding about reaction mixture was stirred at a. high speed for 25 min- 8 grams.

utes and heated externally as needed to maintain reflux. EXAMPLE V During this time the yellow ferric chloride was reduced p to gray ferrous chloride. After addition of 65 mL of dry 10 Preparation of his (1r allyldimtrosyliron)allyltin chloride benzene, nitric oxide was bubbled through the refluxing (Method B) mixture at a rate of 0.25 l./min. for 90 minutes. The Orange crystals of bis(1r-allyl dintrosyliron)tin dichlosolution was then cooled an'd stored under nitrogen at ride prepared in Example I were treated with an equi- 5 C. The solution of u,,u'-dichlorotetranitrosyldiiron 15 molar amount of allylmagnesium bromide at 78 C. contained about 2.4 millimoles dissolved iron per ml. The orange crystals which were crystallized from this Only about 30 percent of the iron, however, was in the mixture were isolated and found to have infrared absorpform of the dichlorotetranitrosyldiiron compound, tion bands for both 1r-allyliron and a-allyltin groups. An the remaining iron being in the form of soluble by-prodelemental analysis which was carried out on this comucts of the catalyst formation. pound agreed with the empirical formula The infrared spectrum of this material is consistent with the indicated structure of this compound and shows C9H1?ClFeN4O4Sn that h 11 1 groups are ,,.b d to h i atom, indicating that one chlorine of the origmal molecule had EXAMPLE H been replaced with an allyl group to give bis(n--allyld1mtrosyliron) allyltin chloride. Preparation of bis(1r-a1lyldinitrosyliron)tin dichloride EXAMPLE VI (Method B) Dimerization of 1,3-butadiene to 4-vinylcyclohexene In e m of the 'dlphlorotetra Butadiene-1,3 was dimerized to 4-vinylcyclohexene nitrosyldnron sohmon (Example I) was Sm-raid under (VCH) using catalysts of the present invention with esmtrogen for several hours with 10 ml. of dry tetrahydrosentiany a quantitative ultimate yield (no by products p of aluminum powder f i l were detected) in a number of batch runs carried out in i dlchlopde a of allyl chlonde' Chilling 100-500 ml. stirred glass reactors immersed in a 40 C. thls reacllon mixture produce? orange. cry.st,als Whlch water bath. Part of the total butadiene charge, generally gave. an mfmred Spectrum which was ldenucal to that about 350 g., was present in the reactor initially and the Obtamed by the crystals of Example rest was added as the reaction proceeded. The reaction EXAMPLE m was virtually complete in about 2 hours when the catalyst was added in the form of the solution in which it was Preparation of bis(ir-allyldinitrosylironfiin dichloride i i n prepared, w h datalyst was added in the (Method C) form of its isolated solid crystals, the reaction, which was carried out at room temperature in this case, took longer (about 24 hours) apparently due to the lower temperature and the time required for complete catalyst solution. The 4-vinylcyclohexene produced in this example has numerous obvious utilities, among which are its The catalyst solution was prepared by stirring, at room temperature and under a nitrogen atmosphere for 35 hours, a mixture of 4.0 ml. of the ,;r'-dichlorotetranitrosyldiiron solution (from Example 1), 10 ml. of dry tetrahydrofuran, 1.0 g. of powdered tin metal, and 0.75 use as a comonomer with ethylene in the production of 'anyl chlqride After stalfdmg several hourstthe p ethylene e'opolymers as described by Giulio Natta et al., ominge solution was cenmfugefl to rempve q French Patent 1,353,179. In addition, it is known to have Sohds and was then found 'actlve for dlmenzauon of utility as a thermal stabilizer for alkyl lea'd compounds as butadlene- EXAMPLE IV disclosed by Thomas et al. in US. Patent 3,197,492.

The following table shows the results obtained using Preparation of bis(1r-allyldinitrosyliron)tin dichloride several catalyst-s of the present invention for the dimeriza- (Method D) tion of 1,3-butadiene.

TABLE L-CATALY'IIC DIMERIZATION OF BUTADIENE CATALYST SYSTEM Productivity, kg. VCH/g. Run No. Catalyst Preparation Quantity mole Fe 1 [(G3H5)(NO)2F6]2 HC Z S0111. of Example I 0.6 mole Fe 570 2.. [(0 115) (NO) Fe]2SnG12 Cr ystallized solid of Example 73.6 mg 870 3 [(C:H5)(NO)2FG12C3H5SHC1 Cgystallized solid of Example 3.1 mg 2500 In this example, the catalyst was prepared by stirring The foregoing data illustrate that the invention catalyst at 50 C., a mixture of 0.17 g .of Roussins black salt, and process are not only very selective, but they are also KFe S (NO) 0.11 g. of anhydrous cadmium chloride, capable of producing 4-vinylcyclohexene from 1,3-buta- 10 ml. of dry tetrahydrofuran, 0.2 ml. of tetraallyltin, cliene in very high yields based on the amount of catalyst and 0.1 g. of powdered zinc. After stirring for about an used. hour, the solution was found active for butadiene dimer- EXAMPLE VII ization.

The Roussins black salt (used in the above paragraph) merization and co-dimerization of was prepared by adding to a boiling solution of 18 g. other conjugated dienes potassium nitrite in 200 ml. of water in a 2-liter beaker, Using the same general procedure described in Exama solution of 20 g. of sodium hydrosulfide in 200 ml. of ple VI, isoprene was dimerized, piperylene was dimerized, water. A solution of 80 g. of ferrous sulfate heptahydrate and a mixture of isoprene and butadiene were co-dimerwith a p of sulfuric acid in 600 ml. of water was then ized using, as a catalyst, a solution of the bis(1r-a1lyldinitrosyliron)tin dichloride prepared in Example I. The results of these tests are shown in the following table.

TABLE II 1,3-butadiene. 39 g. 4-vinylcyelohexene, 7.6 g.

1,4-dimethyl-4-vinylcyclohexcnc.

EXAMPLE VIII Continuous preparation of 4-vinylcyclohexene Butadiene was dimerized to 4-vinylcyclohexene in a continuous process using the catalyst as prepared in Example II. The reactor was tubular being constructed from a 20 foot length of /8" OD stainless steel tubing which was wound into a coil and immersed in a temperature controlled oil bath. The reactor was fed by means of a pump, from an ice-chilled tank containing a prepared mixture of butadiene and catalyst. All portions of the reactor were dried and flushed with dry benzene before and between runs of the test. A pressure of 450 p.s.i.g. was maintained during the runs.

Table III shows a tabulated summary of the results of these runs.

The data in Table III show that the process is easily capable of continuous operation and, under the conditions stated, the preferred reaction temperature appears to be about 60 C. with a residence time of about 1 hour.

Reasonable variation and modification are possible within the spirit and scope of the invention, the essence of which is a new composition of matter having the formula and a process utilizing this composition as a catalyst for the dimerization of conjugated dienes. I

I claim: A 1. A composition of matter comprising a compound having the formula:

FHBTIQKTP I E (NO) 2P6] ZMXZ wherein (CI-IRCRCH is an allylic radical 1r-bonded to the iron atom and in which R is selected from hydrogen and a methyl radical, M is selected from tin, lead, and germanium, and X is selected from chloride, bromide, iodide, and a a-bonded hydrocarbon radical.

2. A composition of matter as defined in claim 1 selected from:

his (vr-allyldinitrosyliron tin dichloride bis (1r-allyldinitrosyliron) tin dibromide bis (1r-allyldinitrosyliron) allyltin chloride bis 1r-allyldinitrosyliron) allyltin bromide bis(1r-allyldinitrosyliron) lead dichloride bis (ir-allyldinitrosyliron) tin diiodide bis(1r-allyldinitrosyliron) germanium dichloride.

TABLE IIL-PRODUOTION OF 4-VINYLCYCLOHEXENE IN CONTINUOUS REACTOR References Cited Bonat et al.: J. Chem. Soc., 1964, p. 179.

TOBIAS E. LEVOW, Primary Examiner.

A. P. DEMERS, Assistant Examiner.

US. Cl. X.R.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No 3,448,129 June 3, 1969 Perry L. Maxfield It is certified that error appears in the above identified patent and that said Letters Patent are hereby corrected as shown below:

Column 2, lines 9 to 15, the formula should appear as shown below:

ON lie s? Fe NO same column 2, lines 22 to 29, the formula should appear as shown below:

:C{2-CH=CH2/NO ON Fe Sn Fe NO I NO c1 Signed and sealed this 20th day of October 1970.

(SEAL) Attest:

EDWARD M. FLETCHER,JR. WILLIAM E. SCHUYLER, JR. Attesting Officer Commissioner of Patents 

1. A COMPOSITION OF MATTER COMPRISING A COMPOUND HAVING THE FORMULA: 